The GMM is an integral part of Littoral Combat Ship (LCS) Surface Warfare (SUW) Mission Package used for counter-piracy, maritime interdiction and security missions. GMM consists of two MK 46 turret mounted, axis-stabilized, 30mm chain gun systems that can fire up to 200 rounds per minute.

Following installation, integration and end-to-end testing was conducted.

"The GMM breaks the paradigm of traditional fixed weapons that require permanent installation into the ship," said Capt. John Ailes, program manager for Program Executive Office Littoral and Mine Warfare's (PEO LMW) LCS Mission Modules program office (PMS 420). "Traditional weapon system installations require the ship to be alongside the pier for an extended upgrade/repair period to accomplish any significant weapon system upgrades/repairs.

Ailes also said the SUW GMM can be upgraded separately from the ship and the updated GMM can then be installed quickly, greatly improving operational tempo.

He added that reverse flexibility of the system is also true, with the GMM capable of being removed and embarked on another LCS platform, reducing the need to procure two GMMs for each platform. The GMM is procured to warfighting requirements and not quantities of ships.

The LCS SUW Mission Package team, lead by Cmdr. William Guarini, PMS 420, installed the GMM on LCS 2.

GMM was the first module of the SUW Mission Package rolled out in July 2008, and consists of an MK44, Mod 2, 30mm automatic chain gun secured in an MK 46 turret. The gun can be fired in single, 5-round bursts and unlimited length bursts. Each GMM has a magazine capacity of more than 800 rounds and fires U.S. Navy 30 X 173mm ammunition. The weapon system is designed to counter small boat threats.

The first Engineering Development Model (EMD) was subsequently installed on LCS 1 and used during Freedom's recent deployment to the U.S. Southern Command's Area of Operations where LCS 1 successfully conducted narcotics trafficking interdiction missions.

Freedom also conducted testing of the GMM recently during the annual Rim of the Pacific Exercise near the Hawaiian islands.

The team also installed the first EDM of the launcher for the Surface-to-Surface Missile Module (SSMM) in the forward centerline weapon zone. LCS 2 is built with a center-line weapon zone and port and starboard weapon zones. Current planning for SUW employment has the 30mm GMM carried in the port and starboard weapon zones and the SSMM carried in the centerline weapon zone.